The present invention disclosed herein relates to a semiconductor integrated circuit and a method of forming the same, and more particularly, to a semiconductor integrated circuit including a grating coupler for optical communication and a method of forming the same.
The present invention has been derived from a research undertaken as a part of the information technology (IT) R & D of Ministry of Information and Communication and Institution for Information Technology Association (MIC/IITA) [2006-S-004-02], silicon based high speed optical interconnection IC.
Recently, technology of a semiconductor integrated circuit has been remarkably developed. Accordingly, the semiconductor integrated circuit becomes faster, lighter, and more highly integrated. These semiconductor integrated circuits can be connected to each other through an electrical signal. However, communication speed between semiconductor integrated circuits or semiconductor integrated circuits and other electronic medium reaches the limitations due to high electrical resistance when semiconductor integrated circuits are connected through electrical signals.
To resolve the above limitations, research for optical communication and/or optical interconnection has been aggressively under development. That is, undertaken actively is research for replacing signals with optical signals between semiconductor integrated circuits, semiconductor integrated circuits and other electronic medium, or small-scale element groups in semiconductor integrated circuits.
As one device for optical communication and/or optical interconnection, a grating coupler was suggested before. The grating coupler couples an optical signal between an optical fiber and a semiconductor integrated circuit. However, this grating coupler has a low optical coupling efficiency, thereby causing massive optical losses.